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Tönu Pullerits. Portrait.

Tönu Pullerits

Professor

Tönu Pullerits. Portrait.

Exciton Relaxation and Polaron Formation in LH2 at Low Temperature

Author

  • Tomáš Polívka
  • Tõnu Pullerits
  • Jennifer L. Herek
  • Villy Sundström

Summary, in English

Excited state dynamics of antenna complexes in an LH2-only mutant of the purple bacterium Rb. sphaeroides have
been investigated by means of two-color femtosecond spectroscopy
combined with computer simulations. Measurements of transient absorption
spectra revealed a new spectral band in the stimulated emission region
around 880 nm at 6 K. To simulate this new dynamic feature that appears
within the first 2 ps after light absorption, we have used a simplified
polaron model via a decoupled red pigment within the B850 ring.
Comparison of simulations and experiment suggests the following kinetic
scheme: (1) initial ultrafast (∼100 fs) dynamics correspond to exciton
relaxation to the lowest exciton state; (2) mixing of the lowest exciton
state with charge-transfer states results in a relaxation to these
states in about 600 fs; (3) picosecond dielectric relaxation in the
charge-transfer states corresponding to polaron formation follows.

Department/s

  • Chemical Physics

Publishing year

2000-02-10

Language

English

Pages

1088-1096

Publication/Series

Journal of Physical Chemistry B

Volume

104

Issue

5

Document type

Journal article

Publisher

The American Chemical Society (ACS)

Topic

  • Physical Chemistry (including Surface- and Colloid Chemistry)

Status

Published

ISBN/ISSN/Other

  • ISSN: 1520-6106